[Instrumented libraries] Fix libidn11 build for Focal

R=thestig

Bug: 1260217
Change-Id: I156d8e6871b1d83913b2767b46d460b12feada16
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3269346
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Auto-Submit: Thomas Anderson <thomasanderson@chromium.org>
Cr-Commit-Position: refs/heads/main@{#940025}
NOKEYCHECK=True
GitOrigin-RevId: ca78ea0695fa4b9319856262ee6b1cf92b144c47